When heavy hydrocarbons such as asphalt, coal tar, heavy oils and crude petroleum are thermally cracked in a reactor, coke is formed as deposits on the inner wall surfaces of the reactor. Accordingly, in order to operate the reactor efficiently on an industrial scale, it is necessary to adequately remove the coke from the inner wall surfaces of the reactor.
In the prior art method of removing coke from the inner wall surfaces of the reactor, the operation of the reactor is suspended and, after cooling the reactor, the coke is mechanically removed by a conventional cleaning method using, for example, a waterjet. Such a method, however, has the disadvantage that continuous operation of the reactor is not possible due to the need to temporarily suspend the operation of the reactor.